In the field of electronic systems, is an interface circuit when is a necessary unit when components of a system are to communicate with one another. Such interface units must serve the function of sending signals to and from the units with which it is in operation and in a manner so that the system is able to operate without malfunctions. This is particularly so in a voice processing system wherein voice data is transferred from a voice processing system to a host computer for the purpose of storing the voice data. Such a system is shown and described in concurrently filed European Patent Application 550274 (U.S. Ser. No. 815,202) and entitled MODULAR DIGITAL VOICE PROCESSING SYSTEM. Unfortunately, suitable interfaces are not available of an acceptable size that are able to perform the functions required with the reliability and speed necessitated in a digital voice processing system. Present state of the art interface circuits required to perform the functions called for in the concurrently filed applications would require to much space to be practicable.